Abstract
BACKGROUND: KIF18A is a regulator of the cell cycle that stimulates the proliferation of cancer cells. The Wnt/β-catenin pathway is involved in different issues' carcinogenesis and is being examined as a therapeutic target. The relationship between KIF18A and β-catenin in breast cancer was not previously investigated. Therefore, this work aims to study the immunohistochemical expression and correlation of KIF18A and β-catenin in breast-infiltrating duct carcinoma (IDC) and their relation to prognosis. MATERIAL AND METHODS: Slides cut from paraffin blocks of 135 IDC and 40 normal breast tissues were stained by KIF18A and β-catenin antibodies. KIF18A cytoplasmic or nucleocytoplasmic staining and β-catenin aberrant expression either nucleo-cytoplasmic or cytoplasmic staining were considered. RESULTS: Normal breast tissue and IDC showed a significant difference regarding KIF18A and aberrant β-catenin expression. High KIF18A and β-catenin H score values were associated with poor prognostic factors such as high grade, advanced stage, distant metastasis, high Ki67 status, and Her2neu-enriched subtype. There was a significant direct correlation between KIF18A and β-catenin as regards percent and H score values. Prolonged overall survival (OS) was significantly associated with mild intensity and low H score of KIF18A, and low β-catenin H score. CONCLUSIONS: KIF18A could be involved in breast carcinogenesis by activating β-catenin. Overexpression of KIF18A and aberrant expression of β-catenin are considered proto-oncogenes of breast cancer development. KIF18A and β-catenin could be poor prognostic markers and predictors of aggressive behavior of breast cancer.